ssid(7) DG/UX 5.4.2 ssid(7)
NAME
ssid - Streams Synchronous Interface Driver
SYNOPSIS
ssid()
ssid(configurationnumber)
ssid@devicecode(VMEaddress)
DESCRIPTION
The ssid driver provides the interface to the VSC/3 and VSC/4
synchronous controller boards. To support this board in the DG/UX
system kernel, you must specify the name of the controller in the
system configuration file. The three formats of the ssid system file
entry are as follows:
Default: ssid()
Shorthand: ssid(configurationnumber)
Fully qualified: ssid@devicecode(VMEaddress)
The ssid requires the devicecode and VMEaddress to configure
properly. The fully qualified format is used to explicitly assign
the devicecode and VME address to the VSC controller to be
configured. The default and shorthand versions of the system file
entry derive this information from the table listed below.
Configuration 0 is the default system file entry.
Configuration Device Code VME Address
0 50 0x55B00000
1 51 0x55B10000
2 52 0x55B20000
3 53 0x55B30000
4 54 0x55B40000
5 55 0x55B50000
6 56 0x55B60000
7 57 0x55B70000
8 58 0xE2080000
9 59 0xE2090000
A 5A 0xE20A0000
B 5B 0xE20B0000
C 5C 0xE20C0000
D 5D 0xE20D0000
E 5E 0xE20E0000
F 5F 0xE20F0000
The device code and VME address must match the jumpering on the VSC
controller. For more information concerning device configuration,
refer to Writing a Device Driver for the DG/UX System.
For each ssid system file entry, six i-nodes in /dev are created as
the ssid devices are configured: four for I/O, one clone device, and
one for direct ssid access.
The /dev i-nodes used for I/O have the format ssidbbu, where bb is a
2 digit board number and u is the unit number. The board number is
Licensed material--property of copyright holder(s) 1
ssid(7) DG/UX 5.4.2 ssid(7)
assigned according to the order that the ssid system file entries
appear in the system file. Thus, the first ssid entry is board 01,
the second entry is board 02, and so on. The unit number specifies a
communications port on the VSC controller. Each I/O device supports
only one open at a time.
The ssid also creates a clone device i-node with the format ssidsbb,
where bb is the assigned board number. The clone device is used to
access board level statistics. The clone device supports multiple
opens. The number of opens supported by the clone device is a system
file parameter.
The /dev i-nodes used for direct ssid access have the format ssidbb,
where bb is the assigned board number. This ssid access device is
used to download the VSC controller. Only one open to this device is
permitted at a time.
In conjunction with the ssid system file entries, there are four
system file variables that are used by the ssid at configuration
time.
System file parameter Alias Name
cfssidtotalwriteiocbs SSIDWRIOCBS
cfssidtotalreadiocbs SSIDRDIOCBS
cfssidtotalcontroliocbs SSIDCTLIOCBS
cfssidtotalclones SSIDCLONES
cfssidtotalwriteiocbs specifies the number of write I/O control
blocks allocated for each unit. A write I/O control block is used to
send output messages to the VSC controller.
cfssidtotalreadiocbs specifies the number of read I/O control
blocks allocated for each unit. A read I/O control block is used to
receive input messages from the VSC controller.
cfssidtotalcontroliocbs specifies the number of control I/O
control blocks allocated for each unit. A control I/O control block
is used to send ioctl or flush messages to the VSC controller.
cfssidtotalclones specifies the number of allowable clone opens
for the clone device.
The system file parameters affect all ssid devices configured on a
system.
EXAMPLES
The following three system file entries are equivalent.
ssid()
ssid(0)
ssid@50(0x55b00000)
If any one of these entries appears in the system file, the ssid
creates the following i-node entries at configuration time:
Licensed material--property of copyright holder(s) 2
ssid(7) DG/UX 5.4.2 ssid(7)
/dev/ssid01 ssid access device (for downloading VSC)
/dev/ssids01 ssid clone device (for statistics)
/dev/ssid010 ssid port A I/O device (for port A I/O)
/dev/ssid011 ssid port B I/O device (for port B I/O)
/dev/ssid012 ssid port C I/O device (for port C I/O)
/dev/ssid013 ssid port D I/O device (for port D I/O)
SEE ALSO
iscd(7), vsxb(7), synccheck(1M), vscload(1M).
NOTES
Baud Rates
The ssid driver supports the following internally generated
baud rates:
1200 2400 4800
9600 19200 38400
48000 56000 64000
In addition to the internal baud rates listed above, the ssid
will accept any external clock data rate up to 64000 bps.
Regardless of the clock source, the ssid will support a
maximum of 2 lines at a data rate of 48000 bps or higher.
Buffer Restrictions
The ssid board resident code has fixed I/O buffer area of
16380 bytes per line. This I/O area may be divided into I/O
buffers according to the following rules:
The sum total of the number of Rx buffers and Tx buffers can
not exceed 30.
The maximum frame size can not exceed 4096 bytes.
The sum total number of buffers (both Rx and Tx) multiplied by
the maximum frame size can not exceed 16380 bytes.
Licensed material--property of copyright holder(s) 3